Portable electric and electronic devices provide users with freedom from power cords and other such power connections, but also have the drawback of periodic recharging or replacement of a charge storage device used to power the portable device, such as a battery. Battery replacement or recharging may be inconvenient for a user, for example, where replacement batteries are not close at hand, or where work must be interrupted to allow rechargeable batteries to recharge.
To overcome such issues, a user may carry a battery charger and an extra battery to allow one battery to be charged while another is in use. However, carrying a charger may be bulky and inconvenient. Likewise, a user may carry an extra charged battery so that the user has a second battery ready for use if the first battery runs out of charge during use. However, carrying an extra charged battery doubles the amount of manual recharging performed later. Further, where a long time between recharging is desired, an extra battery of sufficient size to hold a charge for a desired length of time may be relatively large and costly.